Treatment of Insect Bites
Most insect bites require only symptomatic care with cold compresses and oral antihistamines—antibiotics should NOT be prescribed unless there are clear signs of secondary bacterial infection. 1
Initial Management for Simple Local Reactions
The cornerstone of treatment focuses on symptom relief rather than antibiotics, as the swelling and inflammation result from allergic mediator release, not infection 1, 2:
- Apply cold compresses or ice packs immediately to reduce local pain and swelling 1, 2, 3
- Administer oral antihistamines to reduce itching, pain, and inflammation 1, 2, 3
- Provide oral analgesics (acetaminophen or ibuprofen) for pain management 1, 3
- Elevate the affected limb if swelling is significant 1
- Remove stingers within 10-20 seconds by scraping or flicking away with a fingernail—never grasp and pull the venom sac as this forces more venom into tissue 3
Management of Large Local Reactions
Large local reactions are IgE-mediated allergic inflammation that typically increase in size for 24-48 hours and take 5-10 days to resolve 1:
- Continue cold compresses and oral antihistamines as first-line therapy 1, 3
- Consider oral corticosteroids for severe cases with extensive swelling, initiated promptly within the first 24-48 hours to limit progression, though definitive controlled trial evidence is lacking 1, 2, 3
- Consider allergist referral if large local reactions cause vascular compromise 1
When Antibiotics Are Actually Indicated
Antibiotics should ONLY be prescribed if there are clear signs of secondary bacterial infection 1, 2:
- Progressive redness beyond the initial reaction
- Increasing pain (rather than improving pain)
- Purulent discharge
- Fever
- Warmth and tenderness suggesting cellulitis 1, 2
The evidence shows antibiotics are likely overused for insect bites, with one UK study finding nearly three-quarters of patients received antibiotics despite most having inflammatory reactions rather than true infections 4.
Systemic Reactions and Anaphylaxis
Administer intramuscular epinephrine 0.01 mg/kg (maximum 0.3 mg in children, 0.5 mg in adults) into the anterolateral thigh immediately if systemic symptoms develop 3, 5:
Monitor for systemic reactions including 1:
- Urticaria or angioedema
- Respiratory symptoms (bronchospasm, laryngospasm, airway swelling)
- Cardiovascular symptoms (hypotension, tachycardia, syncope)
- Gastrointestinal symptoms (vomiting, diarrhea, abdominal cramps)
- Neurological symptoms 1, 5
Epinephrine is the ONLY first-line treatment for anaphylaxis—antihistamines and corticosteroids are adjunctive only 3, 5.
Post-Anaphylaxis Management
- Prescribe an epinephrine autoinjector and train caregivers on proper use 3
- Refer to an allergist-immunologist for venom-specific IgE testing and consideration of venom immunotherapy (VIT), which can reduce future systemic reactions 6, 3
Special Considerations
Fire ant stings characteristically produce a sterile pseudopustule within 24 hours that is pathognomonic and NOT infected—leave the vesicle intact and keep clean to prevent secondary infection 1.
Topical corticosteroids (hydrocortisone cream) may provide additional relief for itching associated with minor skin irritations from insect bites 7.
Concentrated heat therapy (applied locally via medical devices) shows promise in real-world studies, with significant reduction in itch (81% reduction at 5-10 minutes for mosquito bites) and pain within minutes of application 8, 9, though this is not yet standard guideline-recommended therapy.
Common Pitfalls to Avoid
- Do not prescribe antibiotics for routine swelling—this is the most common error, as the inflammatory response mimics cellulitis but is actually allergic mediator release 1, 2, 4
- Do not delay epinephrine in systemic reactions—it must be given immediately, not after trying antihistamines 3, 5
- Do not pull out stingers by grasping the venom sac—this injects additional venom 3